Macular degeneration is classified as either dry or wet. The dry form is more common than the wet (about 90% of patients). It may result from the aging and thinning of macular tissues, depositing of pigment in the macula or a combination of the two. In the wet form, new blood vessels grow beneath the retina and leak blood and fluid. This leakage causes retinal cells to die and creates blind spots in central vision.